Piston and spool valve assembly



Feb. 14, 1967 R. c. KURTZ 3,303,855

PISTON AND SPOOL VALVE ASSEMBLY Filed Oct. 28, 1963 INVENTOR. Ronald C. Kurt Attorney United States Patent 3,303,855 PESTGN AND SPOGL VALVE ASSEMBLY Ronaid C. Knrtz, Irwin, Pa., assignor to Westinghouse Air Brake Company, Wilmer-ding, Pa, a corporation of Pennsylvania Filed Get. 23, 1963, Ser. No. 319,367 2 Claims. (Cl. 137-62566) This invention relates generally to a piston and spool valve assembly and relates particularly to modification of either or both ends of a conventional spool valve device to produce a large piston on the spool valve member for operating the spool valve member in response to changes in fluid pressure against the end of the spool valve member within the valve device casing.

Heretofore, in order to provide a pilot-operated low cost spool valve device having a minimum length, the end of the spool valve member has been utilized as the operating piston for effecting movement of the spool valve member. However, this type of construction is disadvantageous in that the optimum diameter of the spool valve member suitable to meet the fluid flow requirements through the valve device is too small to provide a piston area large enough to assure operation of the spool valve member at standard or below standard operating pilot pressures. According- 1y, heretofore, it has been necessary to proportionately increase the diameter of the valve body cavity and the spool valve member in the valve body cavity to provide a sufficiently large piston area on the end of the spool valve member.

The object of the present invention is to provide in a standard spool valve device, a modification of the piston end of the spool valve member providing an enlargement of the diameter of the piston without increasing the length of the spool valve body. In the present invention this is achieved by removing from the valve cavity portions of the liner or sealer assembly disposed in the cavity between the Walls of the valve body and the spool valve member, and substituting therefor a cylinder member fixed in the bore and having an inside diameter substantially larger than the outside diameter of the spool valve member, which cylinder cooperates with a piston member sleeved axially upon the end of the spool valve member is sealed relationship therewith to effectively enlarge the diameter of the spool valve member. The sleeve is slidably disposed within the fixed cylinder member so as to move with the spool valve member in an axial direction in response to the application of fluid pressure to the end of the spool valve member and consequently to the end of the piston member as Well.

These and other objects will become more apparent in view of the following description and in view of the drawings, which, taken in conjunction therewith, disclose the present invention.

The single figure is a sectional view of a spool valve device showing the present invention.

The spool valve device as shown in the drawing generally comprises an elongated valve body member 1 having a bore 2 extending longitudinally therethrough, a spool valve member 3 disposed within said bore 2 for reciprocable movement with respect thereto, and a liner assembly or sealer assembly 4 fitted within the bore 2 between the spool valve member 3 and the valve body 1. A pair of end cap members 5, 6 are disposed each at an opposite end of the vlave body 1 to close the bore 2, which cap members are attached to the valve body 1 in any suitable manner, such as by bolts (not shown). The end cap members 5, 6 each include a bore 7, 8, respectively, disposed therein in coaxial alignment with the bore 2 in valve body 1, which bores 7 and 8 are of slightly lesser diameter than the diameter of bore 2. The valve body 1 3,393,855 Patented Feb. 14, 1967 contains a plurality of passages 9 communicating with the bore 2 and spaced along and around the valve body 1 to facilitate the passage of fluid to and from the bore 2. A pipe element 10 is threadedly received in the external portion of each of the aforementioned passages 9 for connecting the valve body 1 to various fluid circuit devices in a conventional manner.

The liner or spacer assembly 4 comprises a plurality of cylindrical spacer elements 11 having an outside diameter substantially the same as bore 2 and disposed in bore 2 coaxially therewith and in alternate contiguous relationship with a plurality .of annular sealer elements 12. The cylindrical spacer elements 11 each include at least one aperture 13 coinciding with one of the previously mentioned apertures 9 in the valve body 1. Each of the spacer elements 12 includes a pair of concentric resilient rings 14, 15 attached to a metal ring 16 disposed therebetween, the outer ring 15 engaging the bore 2 to provide a seal between the bore 2 and the liner assembly 4, the inner ring engaging the spool member 3 to provide a seal between the spool member 3 and the adjacent apertures 13 in the cylinders 11.

At the left end of the liner assembly 4 there is shown an end spacer element 17 having a cylindrical form similar to spacer element 11 but terminating at its left side at a smaller outer diameter portion 18 extending into the bore 7 in end cap member 5. A spring member 19 is disposed axially of the spool valve member 3 between a composition member 2! fitted in the bottom of bore 7 in end cap member 5 and the end of spool valve member 3.

Ordinarily the right end of the liner assembly 4 as shown in the drawing includes an end spacer member similar to the end spacer member 18 described above. However, in order to accommodate and facilities adaptation of the valve device, as above described, to receive the present invention, the end spacer element normally included at the right end of the liner assembly 4 is omitted, as are also omitted one spacer element 11 and corresponding sealer valve seat member 12 adjacent thereto.

In accordance with the present invention, a cylinder 21 and piston 22 and a sealer element retainer 23 are substituted for the aforementioned omitted end cap member, spacer member and sealer member normally disposed at the right end of the sealer assembly 4. The cylindrical member 21 is apertured at 24 adjacent its inner end to provide passage for fluid to and from the adjacent aperture 9. The outside diameter of the cylinder 21 is substantially the same size as the diameter of bore 2 to provide a tight fit therebetween. An O-ring 25 is provided in a groove in the outside diameter of the cylinder 21 to effect a seal between the cylinder 21 and the bore 2. The inside diameter of the cylinder 21 is substantially larger than the outside diameter of spool valve member 3 providing a space between the cylinder 21 and the spool valve member 3 to accommodate therebetween the piston 22 which comprises a cylindrical member tightly sleeved upon the end of the spool valve member 3 and which is sealed therewith by means of an O-ring 26 disposed in a groove on the inside diameter of the piston 21, and which sleeve is sealed with respect to the cylinder 21 by means of an O-ring 27 disposed in a groove on the outside diameter of the sleeve or piston member 21. The right end of the piston 22 includes an inwardly extending annular shoulder 28 which seats on the tapered end 29 of the spool valve member 3. Aperture means 31 are provided in the right end of the cylinder 21 to permit access of fluid to the end of piston 22 through passage 31 and pipe fitting 32 in the end cap member 6, which pipe fitting 32 is connected to a source of fluid pressure supply (not shown). A composition member 33, similar to composition member 20, is seated in the bore 8 in end cap 3 member 6 to serve as a stop for the spool valve member 3.

In practice, when fluid pressure is provided from the source of supply through fitting 32, passage 31, aperture 30 in cylinder 21 to the end of piston 22, the spool valve member 3 moves to the left from the position shown, the piston 22 seating on tapered end 29, thus transferring the force upon the piston 22 to the end face of the spool valve member 3 so that the combined area of piston 22 and spool valve member 3 present a piston area larger than that of the spool valve member 3 alone, whereby a given fluid pressure effects application of a greater total force to effect movement of the spool valve member 3 reciprocably within the valve body 1. When the fluid pressure is removed, the return spring 19 at the left end of the spool valve member 3 returns the spool valve member 3 and piston 22 to the normal position as shown in the drawing.

Having now described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. A spool valve device, comprising:

(a) a valve body having a bore therein and passage means communicating with said bore,

(b) liner means extending through said bore from one end to a point terminating substantially short of the other end to provide an unlined bore portion, said liner means being appropriately apertured to conduct fluid to and from said passage means,

(c) a spool valve member having alternate grooves and lands of uniform diameter reciprocably disposed in said liner for movement along a path extending from one end of the bore to the other end, and adapted to slide longitudinally in said liner means for interconnecting said passage means in a variety of combinations depending upon the axial position of the member in the bore along said path, one of said lands comprising one extremity of said spool valve member,

(d) said liner means being segmented longitudinally and including between the segments sealing means engageable with the lands on said spool valve member and engageable with said bore to confine the fluid flow to the passage means when said passage means are interconnected in accordance with the position of the spool valve member along said path,

(e) cylinder means disposed in said unlined bore portion in axial juxtaposition with said liner means, the inside diameter of said cylinder means being substantially larger than the diameter of said lands of said spool valve member,

(f) cylindrical sleeve means slidably installed on said one land of said spool valve member in tightly sealed relationship therewith and in slidable sealing relationship With the inside circumference of said cylinder means, and having an inwardly extending shoulder thereon axially engaging the outer end of said one land,

(g) passage means in said body by which to supply fluid under pressure within said cylinder means to the said outer end of said land and the outer end of said sleeve means to move said spool valve member in a first direction along said path to said one end of said bore, and

(h) spring means axially biasing said spool valve member to said other end of said bore in the reverse direction along said path.

2. A piston conversion kit for enlarging the piston area of the spool valve member in a spool valve device including a body having a bore therein and a plurality of passage means communicating with said bore, liner means comprising a plurality of liner segments in said bore and extending from one end thereof to the other end, a spool valve member having alternate grooves andlands of uniform diameter reciprocably disposed in said liner, one of said lands comprising one extremity of said spool valve member with the end of said one land comprising a piston, said spool valve member being movable from one end of said liner to the other in response to fluid pressure applied against said pistons for interconnecting said plurality of passage means in a variety of combinations depending upon the axial position of the spool valve member in said bore, said conversion kit comprising:

(a) cylinder means disposable in one end of said bore in substitution for a predetermined number of said liner segments, the inside diameter of said cylinder being substantially larger than the diameter of said one land at the end of said spool valve member corresponding to said one end of said bore, and

(b) cylindrical sleeve means for slidable installation on said one land of said spool valve member in tightly sealed relationship therewith and having a thickness so as to provide for slidable sealing engagement of the outer periphery thereof with the inside circumference of said cylinder means, and having an inwardly extending shoulder axially engaging the outer end of said one land, whereby fluid pressure is applied to the combined end areas of said one land and said cylindrical sleeve means.

References Cited by the Examiner UNITED STATES PATENTS 2,357,986 9/1944 Wichterman 137-62566 2,852,948 9/1958 Renick l37-625.64 X 2,912,007 11/1959 Johnson 137-625.64 X 2,993,510 7/1961 Collins 137-62564 M. CARY NELSON, Primary Examiner.

HENRY T. KLINSIEK, Examiner. 

1. A SPOOL VALVE DEVICE, COMPRISING: (A) A VALVE BODY HAVING A BORE THEREIN AND PASSAGE MEANS COMMUNICATING WITH SAID BORE, (B) LINER MEANS EXTENDING THROUGH SAID BORE FROM ONE END TO A POINT TERMINATING SUBSTANTIALLY SHORT OF THE OTHER END TO PROVIDE AN UNLINED BORE PORTION, SAID LINER MEANS BEING APPROPRIATELY APERTURED TO CONDUCT FLUID TO AND FROM SAID PASSAGE MEANS, (C) A SPOOL VALVE MEMBER HAVING ALTERNATE GROOVES AND LANDS OF UNIFORM DIAMETER RECIPROCABLY DISPOSED IN SAID LINER FOR MOVEMENT ALONG A PATH EXTENDING FROM ONE END OF THE BORE TO THE OTHER END, AND ADAPTED TO SLIDE LONGITUDINALLY IN SAID LINER MEANS FOR INTERCONNECTING SAID PASSAGE MEANS IN A VARIETY OF COMBINATIONS DEPENDING UPON THE AXIAL POSITION OF THE MEMBER IN THE BORE ALONG SAID PATH, ONE OF SAID LANDS COMPRISING ONE EXTREMITY OF SAID SPOOL VALVE MEMBER, (D) SAID LINER MEANS BEING SEGMENTED LONGITUDINALLY AND INCLUDING BETWEEN THE SEGMENTS SEALING MEANS ENGAGEABLE WITH THE LANDS ON SAID SPOOL VALVE MEMBER AND ENGAGEABLE WITH SAID BORE TO CONFINE THE FLUID FLOW TO THE PASSAGE MEANS WHEN SAID PASSAGE MEANS ARE INTERCONNECTED IN ACCORDANCE WITH THE POSITION OF THE SPOOL VALVE MEMBER ALONG SAID PATH, (E) CYLINDER MEANS DISPOSED IN SAID UNLINED BORE PORTION IN AXIAL JUXTAPOSITION WITH SAID LINER MEANS, THE INSIDE DIAMETER OF SAID CYLINDER MEANS BEIKNG SUBSTANTIALLY LARGER THAN THE DIAMETER OF SAID LANDS OF SAID SPOOL VALVE MEMBER, (F) CYLINDRICAL SLEEVE MEANS SLIDABLY INSTALLED ON SAID ONE LAND OF SAID SPOOL VALVE MEMBER IN TIGHTLY SEALED RELATIONSHIP THEREWITH AND IN SLIDABLE SEALING RELATIONSHIP WITH THE INSIDE CIRCUMFERENCE OF SAID CYLINDER MEANS, AND HAVING AN INWARDLY EXTENDING SHOULDER THEREON AXIALLY ENGAGING THE OUTER END OF SAID ONE LAND, (G) PASSAGE MEANS IN SAID BODY BY WHICH TO SUPPLY FLUID UNDER PRESSURE WITHIN SAID CYLINDER MEANS TO THE SAID OUTER END OF SAID LAND AND THE OUTER END OF SAID SLEEVE MEANS TO MOVE SAID SPOOL VALVE MEMBER IN A FIRST DIRECTION ALONG SAID PATH TO SAID ONE END OF SAID BORE, AND (H) SPRING MEANS AXIALLY BIASING SAID SPOOL VALVE MEMBER TO SAID OTHER END OF SAID BORE IN THE REVERSE DIRECTION ALONG SAID PATH. 